The US special counsel prosecuting Donald Trump on federal charges of trying to overturn his 2020 election defeat has asked the Supreme Court to launch a fast-track review of the former president's claim he cannot be tried on those charges. Trump has appealed a decision by US District Judge Tanya Chutkan on December 1 rejecting his bid to dismiss the case. The judge found no legal support for the position argued by Trump's lawyers that former presidents cannot face criminal charges for conduct related to their official responsibilities. It is rare for a prosecutor to ask the Supreme Court to intervene in a case before a lower appeals court has already ruled but US Special Counsel Jack Smith's move reflects the urgency of the case ahead of the November 5 election. If re-elected, Trump could seek to pardon himself of any federal crimes. Smith told the Supreme Court in a written filing that the "case presents a fundamental question at the heart of our democracy". Trump's appeal suspends his trial, which was scheduled to begin on March 4. "It is of imperative public importance that (Trump's) claims of immunity be resolved by this court and that (Trump's) trial proceed as promptly as possible if his claim of immunity is rejected," Smith said. Smith insisted claims by Trump, the frontrunner for the 2024 Republican presidential nomination, are "profoundly mistaken," adding that only the Supreme Court "can definitively resolve them". Legal experts have said that Trump's lawyers could use his immunity appeals to delay the trial, freeing him to campaign against Democratic President Joe Biden. Prosecutors have accused Trump of attempting to obstruct Congress and defraud the US government through schemes to overturn his loss to Biden in 2020. Trump faces four counts related to his efforts to overturn the 2020 election results. These included: conspiracy to obstruct an official proceeding; obstruction of and attempt to obstruct an official proceeding; conspiracy to defraud the United States; and conspiracy to deprive citizens of their voting rights. Trump has pleaded not guilty to these charges as well as charges stemming from three other ongoing criminal prosecutions. Trump has accused prosecutors of attempting to damage his campaign. Smith asked the justices on Monday to resolve whether a former president is absolutely immune from federal prosecution for conduct undertaken in office, and "the effect, if any, that his acquittal in impeachment proceedings has on this federal prosecution". Smith asked the court to fast-track the written submissions required in the case, urging a December 18 deadline for Trump to file a response to his petition. Three of the nine justices were appointed by Trump, who cemented a 6-3 conservative majority on the court. Australian Associated Press